title: Transcriptional engineering of Escherichia coli K4 for fructosylated chondroitin production.
abstract: The capsule polysaccharide (CPS) of Escherichia coli K4 (K4CPS) is identical to fructosylated chondroitin, which can be modified to chondroitin sulfate, a commercially valuable biopolymer commonly used in pharmaceutical applications. In this study, we homologously overexpressed the transcriptional regulator SlyA to enhance the expression of K4 capsule gene cluster and production of CPS. The iTRAQ quantificaton of proteomics revealed 77 up-regulated proteins and 143 down-regulated proteins in E. coli THslyA. Most enzymes of glycolysis and citrate cycle pathway were weakened, while proteins associated with K4CPS synthesis were up-regulated, showing a shift of carbon flux from cell growth to K4CPS production. Further, the production of K4CPS by the recombinant strain was 1 and 2.6 g/L in a shake flask and 7-L batch bioreactor, which was 1.85- and 1.53-fold higher than that of the wild-type strain, respectively. Thus, this study provides a viable strategy for improving the production of K4CPS through a transcriptional-level manipulation.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu, 214122, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, 214122, China.
authors.forename: Qiulin
authors.initials: Q
authors.lastname: Wu
authors.forename: Aihua
authors.initials: A
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Zou
authors.forename: Zuoying
authors.initials: Z
authors.lastname: Duan
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Liming
authors.initials: L
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D019149:Bioreactors; D002807:Chondroitin / Q000096:biosynthesis*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering / Q000379:methods*; D005810:Multigene Family; D011134:Polysaccharides / Q000378:metabolism; D020543:Proteome; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D011134:Polysaccharides; D020543:Proteome; D014157:Transcription Factors; C056785:salmolysin; D002807:Chondroitin
keywords: E. coli K4; capsule polysaccharide; chondroitin sulfate; slyA; transcriptional regulation